// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_CAST_SENDER_VP8_ENCODER_H_
#define MEDIA_CAST_SENDER_VP8_ENCODER_H_

#include <stdint.h>

#include <memory>

#include "base/macros.h"
#include "base/threading/thread_checker.h"
#include "media/base/feedback_signal_accumulator.h"
#include "media/cast/cast_config.h"
#include "media/cast/sender/software_video_encoder.h"
#include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
#include "ui/gfx/geometry/size.h"

namespace media {
class VideoFrame;
}

namespace media {
namespace cast {

    class Vp8Encoder : public SoftwareVideoEncoder {
    public:
        explicit Vp8Encoder(const FrameSenderConfig& video_config);

        ~Vp8Encoder() final;

        // SoftwareVideoEncoder implementations.
        void Initialize() final;
        void Encode(const scoped_refptr<media::VideoFrame>& video_frame,
            const base::TimeTicks& reference_time,
            SenderEncodedFrame* encoded_frame) final;
        void UpdateRates(uint32_t new_bitrate) final;
        void GenerateKeyFrame() final;

    private:
        bool is_initialized() const
        {
            // ConfigureForNewFrameSize() sets the timebase denominator value to
            // non-zero if the encoder is successfully initialized, and it is zero
            // otherwise.
            return config_.g_timebase.den != 0;
        }

        // If the |encoder_| is live, attempt reconfiguration to allow it to encode
        // frames at a new |frame_size|.  Otherwise, tear it down and re-create a new
        // |encoder_| instance.
        void ConfigureForNewFrameSize(const gfx::Size& frame_size);

        const FrameSenderConfig cast_config_;

        const double target_encoder_utilization_;

        // VP8 internal objects.  These are valid for use only while is_initialized()
        // returns true.
        vpx_codec_enc_cfg_t config_;
        vpx_codec_ctx_t encoder_;

        // Set to true to request the next frame emitted by Vp8Encoder be a key frame.
        bool key_frame_requested_;

        // Saves the current bitrate setting, for when the |encoder_| is reconfigured
        // for different frame sizes.
        int bitrate_kbit_;

        // The |VideoFrame::timestamp()| of the last encoded frame.  This is used to
        // predict the duration of the next frame.
        base::TimeDelta last_frame_timestamp_;

        // The ID for the next frame to be emitted.
        FrameId next_frame_id_;

        // This is bound to the thread where Initialize() is called.
        base::ThreadChecker thread_checker_;

        // Set to true once a frame with zero-length encoded data has been
        // encountered.
        // TODO(miu): Remove after discovering cause.  http://crbug.com/519022
        bool has_seen_zero_length_encoded_frame_;

        // The accumulator (time averaging) of the encoding speed.
        FeedbackSignalAccumulator<base::TimeDelta> encoding_speed_acc_;

        // The higher the speed, the less CPU usage, and the lower quality.
        int encoding_speed_;

        DISALLOW_COPY_AND_ASSIGN(Vp8Encoder);
    };

} // namespace cast
} // namespace media

#endif // MEDIA_CAST_SENDER_VP8_ENCODER_H_
